For me Flipkart would seem better just because of their tech stack seems better than Microsoft’s since I don’t want to work on that personally. But TBH, java is also getting pretty old and people are moving on to newer languages like python and go, however demand for java will still be there for decades to come but maybe not as much as other new languages.
Personally I don’t want to leave Bangalore, first it was for weather now even I am not so sure😂, This makes your question also very personal to you, both packages are great, it all comes down to what you want in near future and where do you see your life headed, at your age there are too many possible options and you never know which path might take you where.
Do consider in each scenario how your daily life would look like, what would be your goals as soon as you switch, etc and if it seems good then choose that.
One more thing, try to get to know about work culture, wfh policy and manager first as they will set your tone for next few years.
Good luck and congratulations 🥂
Do tell what you decided and why?